WITH SUB AS (
  SELECT
    AVG(POINT) AS AVE
  FROM
    TEST_RESULTS
  WHERE
   TEST_ID = '100'
),SUB2 AS(
  SELECT
    SQRT(AVG(POW(A.POINT - B.AVE,2))) AS HH
  FROM
  TEST_RESULTS A
  ,SUB B
  WHERE
  TEST_ID = '100'
)
SELECT
A.USER_ID AS USER
,A.POINT AS PT
,CASE 
  WHEN C.HH = 0
    THEN 50
  ELSE
   ROUND((((A.POINT - B.AVE) * 10) / C.HH) + 50,1)
END AS DEV_VAL 
FROM
TEST_RESULTS A
,SUB B
,SUB2 C
WHERE
TEST_ID = '100'
ORDER BY
DEV_VAL DESC
,USER ASC
;